The present invention relates to multi-phase pipelines wherein multiple fluid phases flow through a single pipeline and, more particularly, to the determination of the flow rates and film heights of the different fluid phases flowing within the pipeline.
In a variety of industrial and experimental applications, it is necessary to monitor the flow of a collection of fluids in a pipeline. For example, in the oil and gas industry, distinct fluid phases, e.g, a liquid phase and a gaseous or vapor phase, exist in horizontal pipelines. Multi-phase flow metering, wherein the velocity and flow rate of each fluid phase flowing within a pipeline is metered, presents the potential for a valuable tool for the oil and gas industry. Many of the conventional multi-phase flow metering systems do not provide an accurate indication of the flow rate of each fluid phase flowing within a pipeline because of inherent limitations in their methodology. Further, other conventional systems are prohibitively difficult to install or incorporate intrusive metering arrangements requiring interruption or alteration of the multi-phase flow. Finally, many conventional systems are merely compatible with a limited range of pipeline designs and, accordingly, have limited utility.
Accordingly, there is a need for a multi-phase flow metering system and method incorporating a non-intrusive, versatile, accurate, readily installable, and cost effective multi-phase fluid metering design.
This need is met by the present invention wherein an improved method and apparatus for determining gas and liquid flow rates in a multi-phase flow are provided. In accordance with one embodiment of the present invention, a method of determining gas and liquid flow rates in a multi-phase flow is provided. The method utilizes a set of gas phase ultrasonic transducers and a set of liquid phase ultrasonic transducers positioned to direct ultrasonic signals through the multi-phase flow. The method comprising the steps of: (i) establishing a set of gas phase control parameters and a gas phase algorithm for determining a flow rate of a gaseous portion of the multi-phase flow, wherein the gas phase control parameters define a gas phase ultrasonic signal characterized by a gas phase center frequency and a gas phase bandwidth and the gas phase algorithm comprises at least one of a gas phase transit time algorithm and a gas phase cross correlation algorithm; (ii) establishing a set of liquid phase control parameters and a liquid phase algorithm for determining a flow rate of a liquid portion of the multi-phase flow, wherein the liquid phase control parameters define a liquid phase ultrasonic signal characterized by a liquid phase center frequency and a liquid phase bandwidth and the liquid phase algorithm comprises a liquid phase cross correlation algorithm; (iii) controlling the gas phase ultrasonic transducers according to the gas phase control parameters so as to transmit the gas phase ultrasonic signal; (iv) analyzing the gas phase ultrasonic signal according to the gas phase algorithm; (v) controlling the liquid phase ultrasonic transducers according to the liquid phase control parameters so as to transmit a liquid phase ultrasonic signal; (vi) analyzing the liquid phase ultrasonic signal according to the liquid phase algorithm; and (vii) determining the gas and liquid flow rates based upon the analyses of the gas phase ultrasonic signal and the liquid phase ultrasonic signal.
The method may further comprise the steps of: establishing the gas phase control parameters for a plurality of sets of the gas phase ultrasonic transducers such that the gas phase control parameters define a plurality of gas phase ultrasonic signals; establishing the liquid phase control parameters for a plurality of sets of the liquid phase ultrasonic transducers such that the liquid phase control parameters define a plurality of liquid phase ultrasonic signals; and analyzing the gas phase and the liquid phase ultrasonic signals with the aid of an ultrasonic data selection terminal, wherein the ultrasonic data selection terminal is controlled so as to establish a dwell time for each set of the plurality of sets of ultrasonic transducers.
The method may further comprise the step of establishing the gas phase control parameters for a plurality of sets of the gas phase ultrasonic transducers such that the gas phase control parameters define a plurality of gas phase ultrasonic signals. The method may also comprise the step of analyzing the gas phase ultrasonic signals with the aid of an ultrasonic data selection terminal, wherein the ultrasonic data selection terminal is controlled so as to establish a dwell time for each set of the plurality of sets of the gas phase ultrasonic transducers.
The method may further comprising the step of establishing the liquid phase control parameters for a plurality of sets of the liquid phase ultrasonic transducers such that the liquid phase control parameters define a plurality of liquid phase ultrasonic signals. The liquid phase ultrasonic signals may be analyzed with the aid of an ultrasonic data selection terminal, wherein the ultrasonic data selection terminal is controlled so as to establish a dwell time for each set of the plurality of sets of the liquid phase ultrasonic transducers.
The method may further comprise the step of analyzing the liquid phase ultrasonic signals according to a plurality of liquid phase algorithms with the aid of an ultrasonic data selection terminal, wherein the ultrasonic data selection terminal is controlled so as to establish a dwell time for each algorithm of the plurality of liquid phase algorithms. The gas phase ultrasonic signals may be analyzed according to a plurality of gas phase algorithms with the aid of an ultrasonic data selection terminal, wherein the ultrasonic data selection terminal is controlled so as to establish a dwell time for each algorithm of the plurality of gas phase algorithms.
The method may further comprise the step of analyzing the liquid phase ultrasonic signals according to a plurality of sets of liquid phase control parameters with the aid of an ultrasonic data selection terminal, wherein the ultrasonic data selection terminal is controlled so as to establish a dwell time for each set of the plurality of sets of liquid phase control parameters. Similarly, the method may further comprise the step of analyzing the gas phase ultrasonic signals according to a plurality of sets of gas phase control parameters with the aid of an ultrasonic data selection terminal, wherein the ultrasonic data selection terminal is controlled so as to establish a dwell time for each set of the plurality of sets of gas phase control parameters.
The liquid phase algorithm may further comprise a liquid phase pulse echo mode algorithm. The step of establishing the gas phase algorithm may be characterized by a preference for the gas phase cross correlation algorithm over the gas phase transit time algorithm as an amount of liquid in the multi-phase flow increases.
The multi-phase flow may be contained within a pipeline, the gas phase ultrasonic signal is transmitted by coupling the set of gas phase ultrasonic transducers to an exterior surface of the pipeline, the liquid phase ultrasonic signal may be transmitted by coupling the set of liquid phase ultrasonic transducers to the exterior surface of the pipeline.
The gas phase ultrasonic signal may also be transmitted by coupling the set of gas phase ultrasonic transducers to an exterior surface of the pipeline. The set of gas phase ultrasonic transducers may comprise at least one upstream gas phase ultrasonic transducer and at least one downstream gas phase ultrasonic transducer positioned on opposite sides of a central longitudinal axis of the pipeline. The liquid phase ultrasonic signal may be transmitted by coupling the set of liquid phase ultrasonic transducers to an exterior surface of the pipeline. The set of liquid phase ultrasonic transducers may comprise at least one upstream liquid phase ultrasonic transducer and at least one downstream liquid phase ultrasonic transducer positioned on a common side of the central longitudinal axis of the pipeline. The set of gas phase ultrasonic transducers may comprise at least one upstream gas phase ultrasonic transducer and at least one downstream gas phase ultrasonic transducer positioned on a common side of a central longitudinal axis of the pipeline.
The gas phase center frequency may represent a compromise between unacceptable signal divergence at frequencies below or near 100 kHz and unacceptable signal attenuation at frequencies above or near 1 MHz.
In accordance with another embodiment of the present invention, a method of determining gas and liquid flow rates in a multi-phase flow contained within a pipeline is provided. The method utilizes a plurality of sets of gas phase ultrasonic transducers and a plurality of sets of liquid phase ultrasonic transducers positioned to direct ultrasonic signals through the multi-phase flow. The method comprises the steps of: (i) establishing a set of gas phase control parameters for the sets of the gas phase ultrasonic transducers such that the gas phase control parameters define a plurality of gas phase ultrasonic signals; (ii) establishing a gas phase algorithm for determining a flow rate of a gaseous portion of the multi-phase flow, wherein the gas phase control parameters define gas phase ultrasonic signals characterized by respective gas phase center frequencies and gas phase bandwidths and the gas phase algorithm comprises at least one of a gas phase transit time algorithm and a gas phase cross correlation algorithm; (iii) establishing a set of liquid phase control parameters for the plurality of sets of the liquid phase ultrasonic transducers such that the liquid phase control define a plurality of liquid phase ultrasonic signals; (iv) establishing a liquid phase algorithm for determining a flow rate of a liquid portion of the multi-phase flow, wherein the liquid phase control parameters define liquid phase ultrasonic signals characterized by respective liquid phase center frequencies and liquid phase bandwidths and the liquid phase algorithm comprises a liquid phase cross correlation algorithm; (v) coupling the set of gas phase ultrasonic transducers to an exterior surface of the pipeline, wherein the set of gas phase ultrasonic transducers comprise at least one upstream gas phase ultrasonic transducer and at least one downstream gas phase ultrasonic transducer; (vi) controlling the gas phase ultrasonic transducers according to the gas phase control parameters so as to transmit the gas phase ultrasonic signals; (vii) analyzing the gas phase ultrasonic signals according to the gas phase algorithm with the aid of an ultrasonic data selection terminal, wherein the ultrasonic data selection terminal is controlled so as to establish a dwell time for each set of the plurality of sets of gas phase ultrasonic transducers; (viii) coupling the set of liquid phase ultrasonic transducers to an exterior surface of the pipeline wherein the set of liquid phase ultrasonic transducers comprise at least one upstream liquid phase ultrasonic transducer and at least one downstream liquid phase ultrasonic transducer; (ix) controlling the liquid phase ultrasonic transducers according to the liquid phase control parameters so as to transmit the liquid phase ultrasonic signals; (x) analyzing the liquid phase ultrasonic signals according to the liquid phase algorithm with the aid of the ultrasonic data selection terminal, wherein the ultrasonic data selection terminal is controlled so as to establish a dwell time for each set of the plurality of sets of liquid phase ultrasonic transducers; and (xi) determining the gas and liquid flow rates based upon the analyses of the gas phase ultrasonic signals and the liquid phase ultrasonic signals.
In accordance with yet another embodiment of the present invention, a system for determining gas and liquid flow rates in a multi-phase flow contained within a pipeline is provided. The system comprises a plurality of sets of gas and liquid phase ultrasonic transducers and a flow rate analyzer. The gas phase ultrasonic transducers are coupled to an exterior surface of the pipeline and comprise at least one upstream gas phase ultrasonic transducer and at least one downstream gas phase ultrasonic transducer. The liquid phase ultrasonic transducers are coupled to an exterior surface of the pipeline and comprise at least one upstream liquid phase ultrasonic transducer and at least one downstream liquid phase ultrasonic transducer. The flow rate analyzer is programmed to (i) establish a set of gas phase control parameters for the plurality of sets of gas phase ultrasonic transducers such that the gas phase control parameters define a plurality of gas phase ultrasonic signals, (ii) establish a gas phase algorithm for determining a flow rate of a gaseous portion of the multi-phase flow, wherein the gas phase control parameters define gas phase ultrasonic signals characterized by respective gas phase center frequencies and gas phase bandwidths and the gas phase algorithm comprises at least one of a gas phase transit time algorithm and a gas phase cross correlation algorithm (iii) establish a set of liquid phase control parameters for the plurality of sets of the liquid phase ultrasonic transducers such that the liquid phase control parameters define a plurality of liquid phase ultrasonic signals; (iv) establish a liquid phase algorithm for determining a flow rate of a liquid portion of the multi-phase flow, wherein the liquid phase control parameters define liquid phase ultrasonic signals characterized by respective liquid phase center frequencies and liquid phase bandwidths and the liquid phase algorithm comprises a liquid phase cross correlation algorithm; (v) control the gas phase ultrasonic transducers according to the gas phase control parameters so as to transmit the gas phase ultrasonic signals; (vi) analyze the gas phase ultrasonic signals according to the gas phase algorithm with the aid of an ultrasonic data selection terminal, wherein the ultrasonic data selection terminal is controlled so as to establish a dwell time for each set of the plurality of sets of gas phase ultrasonic transducers;(vii) control the liquid phase ultrasonic transducers according to the liquid phase control parameters so as to transmit the liquid phase ultrasonic signals; (viii) analyze the liquid phase ultrasonic signals according to the liquid phase algorithm with the aid of the ultrasonic data selection terminal, wherein the ultrasonic data selection terminal is controlled so as to establish a dwell time for each set of the plurality of sets of liquid phase ultrasonic transducers; and (ix) determine the gas and liquid flow rates based upon the analyses of the gas phase ultrasonic signals and the liquid phase ultrasonic signals.
Accordingly, it is an object of the present invention to provide an improved scheme for determining gas and liquid flow rates in a multi-phase flow. Other objects of the present invention will be apparent in light of the description of the invention embodied herein.